FILM / Age to age: It should come as no surprise that, when Martin Scorsese turned to the classics, Edith Wharton caught his eye.

The old film world maxim that good books make bad movies - or, more pungently, that you're better off adapting from James M Cain than from Dostoyevsky - has received a major body blow. Martin Scorsese's The Age of Innocence has not only confounded all the wiseguys who predicted that his foray into ballgown drama would turn out to be an extravagant folly (it has won rapturous notices and dollars 50m box-office to date), but proved that a good movie could be made from the kind of uncommonly good book that usually nestles in the cool tranquillity of library stacks. The novels of Edith Wharton (1862-1937) had long been regarded as classics; suddenly, they started to look like hot movie properties, too.

This development was all the more improbable in view of the fact that her Age of Innocence (1921) had already been made into a quite dismal movie: a 1934 RKO feature, to be exact, starring Irene Dunne and John Boles, directed by Philip Moeller, and described by one of the few people to have seen it recently - Scorsese's editor, Thelma Schoonmaker - as so ponderous that it was impossible to sit through. And yet Hollywood might have taken up Mrs Wharton anyway, albeit in more modest style, even if Scorsese had dropped the Innocence scheme and decided to switch to one of his other floating projects, such as Clockers (from the decidedly un-Whartonian novel about drug-dealers by Richard Price) or Gershwin (from the screenplay by Paul Schrader) instead.

A film of Ethan Frome (1911), the short novel for which Edith Wharton has been best known in America, opened in the US at almost exactly the same time as Scorsese's production, and comes to Britain next month. Though overshadowed by Innocence, it bears highly respectable credits, including Liam Neeson in the title- role and a screenplay by the talented playwright Richard Nelson. Moreover, a television film of Wharton's The House of Mirth (1905) has already been made in Canada, and Ken Russell has long wanted to bring it to larger screens; and BBC drama is reported to be developing her final, unfinished novel The Buccaneers (1938).

What is it about Wharton that film- makers find so strangely attractive? Something, perhaps, like the qualities which pull Newland Archer, the hero of Age of Innocence (played by Daniel Day-Lewis), away from the propriety of his marriage to innocent May Welland (Winona Ryder) and into the arms of Countess Olenska (Michelle Pfeiffer): her paradoxical combination of familiarity and exoticism, warm promise and aloof challenge.

Edith Wharton's books, that is to say, are at once highly filmable and superbly resistant to filming. According to Scorsese's co-screenwriter, Jay Cocks, the director was first drawn to the novel in the early Eighties, around the time of Raging Bull, because its tale of thwarted love seemed to echo his own amorous troubles. However, Cocks continued, it was the book's more formal attractions of style and structure that then held him.

It is not simply that she is a novelist with a strong visual sense, or one who knows how to propel a narrative on a sequence of symbolic incidents - meaningful glances, the decorous manoeuvring of bodies in a social arena. (Some of the most typically cinematic touches in Scorsese's film - such as the conversation between Newland and the Countess which is punctuated by the fall of logs in a fireplace - are taken directly from the page.) More importantly, she has a strongly analytical visual sense, particularly when the scene in question is that of the densely, delicately coded world of 'old New York' and its sumptuous dressings - her first successful work, in 1897, was a non-fiction book entitled The Decoration of Houses.

A thoughtless director would take such passages as nothing more than an ideal cue to wheel out the pretty frocks and fancy china, but a good director will realise that Wharton's characters, in the words of Oscar Wilde's pregnant witticism, have to live up to their china. Indeed, her accounts of decor are as scrupulous, or scientific, as any anthropologist's field study, and a cineaste should try to film them in the same spirit of sceptical fascination. To Wharton's mind, a place setting is as charged with tribal meaning as a necklace of cowrie shells.

Indeed, in Age of Innocence she habitually refers to her upper classes as a 'tribe', and makes great play of such ethnographical metaphors: 'It was 'not the thing' to arrive early at the Opera; and what was or was not 'the thing' played a part as important in Newland Archer's New York as the inscrutable tribal totems that had ruled the destinies of his forefathers thousands of years ago.' In elaborating this thought, she is sometimes very close to the pioneering sociologist Thorstein Veblen, who in his Theory of the Leisure Class rudely compared the habits of America's rich to those of barbarian warlords - though she can be compassionate where Veblen is only sarcastic.

In a different way, her novels are also - bizarre as the comparison may seem in view of their wildly differing content - remarkably close to the spirit of a Scorsese film such as GoodFellas, which, disregarding all the guns and the coke and the kitchen knives, is a minutely textured re- creation of the weddings, the feasts, the manners and, yes, even the decorative sense of another small and self-engrossed slice of New York society. Edith might not have liked all the harsh language and the lashings of ketchup, but she would surely have respected Marty's lynx eye for significant detail.

The novelist and the director are also at one in their unblinking recognition of the ruthlessness with which their respective cliques defend their turf. True, no one in Wharton's New York has their brains blown out with an automatic, but she is well aware that the smart set's reprisals have a finality of their own. There is a dinner party scene towards the end of the novel in which Newland Archer suddenly recognises that the guests around him are 'a band of dumb conspirators', dead set on the destruction of his adulterous love for Ellen Olenska. 'It was the old New York way of taking life 'without effusion of blood': the way of people who dreaded scandal more than disease, and who considered that nothing was more ill-bred than 'scenes', except the behavior of those who gave rise to them.' It is a dismaying moment in print, and in Scorsese's film it is every bit as chilling as the moment in GoodFellas when Joe Pesci is 'whacked'.

The virtue that Scorsese found most tempting in Edith Wharton, though, was not her anthropological thrust, nor her economical narrative, nor her visual sense, but the single quality that most resists any ardent suitor from Hollywood: her style. Scorsese, probably the most cine-literate director in the world, has come late to the joys of reading, and as with many late- blooming passions, his love for Wharton's prose has its recklessness. Alas, like Henry James (the comparison is routine: James was Wharton's friend, and wisely told her to use her 'American voice' - to write about the world she knew, rather than the medieval world of her early novel The Valley of Decision), Wharton is a writer whose authorial voice is as important as anything in her plot.

A director may attempt - and Scorsese has attempted - to find some filmic analogies for the vigilance of her style, with its quick humour, careful tartness and sudden opening of unexpected vistas; but there are large tracts of the novel that must always remain inaccessible to the adaptor. How could any director hope adequately to render, say, Newland Archer's contemplation of his fiancee? '. . . The young creature whose soul's custodian he was to be. That terrifying product of the social system he belonged to and believed in, the young girl who knew nothing and expected everything, looked back at him like a stranger through May Welland's familiar features . . .'

Scorsese has tried to retain some fragments of this tone by using the device of an intermittent voice-over - also his way of nodding to some of the narrated films that have made their own contributions to his Age of Innocence, from Orson Welles's Magnificent Ambersons to Stanley Kubrick's Barry Lyndon (films, both of them, that took similarly idiosyncratic approaches to the vexed task of bringing novels to the screen). It's an honourable gesture, but more often than not it comes to serve as the film's most powerful reminder of all those flashes of Wharton's intelligence and wit that Scorsese, for all his gifts, can't translate into pictures. Edith Wharton may excel in the portrayal of grand balls and formal dances; but her real genius is to be found in her style - in her execution of, in Ezra Pound's phrase, the dance of intellect among words.

'The Age of Innocence' opens tomorrow; Adam Mars-Jones' review will appear then. 'Ethan Frome' is at the NFT, 11-20 Feb